Countertop humidifier



FIG. 1 is a perspective view of a countertop humidifier showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The dashed or broken lines shown in the drawings depict portions of the countertop humidifier in which the design is embodied that form no part of the claimed design. 

CLAIM The ornamental design for a countertop humidifier, as shown and described. 